For the first time since 1976, a strain of influenza virus - apparently related to the 1918-19 pandemic - has infected the public. More than 1,000 cases have been reported in Mexico, with over 80 deaths. And the disease has now spread to several areas within the United States and to New Zealand. The virus has been identified by the American Centres for Disease Control and Prevention (CDC) as type H1N1, containing a mixture of swine, avian and human genetic material.

This outbreak of influenza is viewed with alarm by public health workers. First, because the earlier pandemic was so deadly; second, because this is the first clear demonstration of human-to-human spread of the infection; and third, because it apparently started its spread after the normal "flu season" in the northern hemisphere.

However, the world may be much better prepared to cope with this outbreak than before. One reason is that an earlier swine flu outbreak in the US, in 1976, found both the political and medical/public health worlds unprepared to cope with what appeared to be a serious threat of pandemic spread. Fortunately, the outbreak never came, but many of the lessons of that era were well learned - especially by the public health community.

Thus, when avian flu seemed to threaten the world in recent years, both national public health bureaus around the world and the World Health Organisation organised themselves for action and began to stockpile anti-flu drugs and to ramp up the facilities for vaccine formation. These efforts have facilitated the early response measures for the current swine flu threat. Both the CDC and the WHO have mobilised to assist the Mexicans, and health offices across the world are becoming active.

It is clear from the above that public health workers are better prepared to deal with this threat. Science is also better prepared than it was earlier - the genome of the virus was quickly analysed and seed stocks for vaccine production isolated (although it will take many months to prepare enough doses to immunise large populations against the prevalent strain of virus).

Medicine is also better prepared, since it can distribute the already stockpiled antiviral drugs, and has far better treatments for the pneumonias and other secondary problems that threaten life.

This is not to say that a pandemic, if it does indeed come, will not be serious. The illness of large numbers of people, even when the infection itself is not directly life-threatening, is often accompanied by severe social disruptions. Schools close, normal pursuits suffer, and emergency rooms and the entire healthcare system become seriously overloaded. History demonstrates that the greatest threat from even a mild disease that affects large numbers of individuals simultaneously may come from the accompanying social disruption and lack of nursing care available to the sick.

Thus, while the professionals may be better prepared to deal with a threatened pandemic, it is not yet clear that the politicians around the world have learned the same lessons. Governments might have to nationalise their healthcare systems in order to cope, just as they have had to do recently with their financial systems - something that might be far more difficult in the US than in Britain and elsewhere.

• Dr Arthur Silverstein, a professional immunologist and professor emeritus at Johns Hopkins University medical school, is author of Pure Politics and Impure Science: The Swine Flu Affair